Microsoft has been extremely quiet regarding the upcoming “Update 3” for Windows RT 8.1 users, which is set to land sometime this September. We first learned about the existence of Update 3 back in January, where Microsoft confirmed Windows RT 8.1 would not be receiving the full Windows 10 treatment.

Microsoft’s original statement claimed that Windows RT 8.1 users would receive a subset of Windows 10 features, but were not specific on what features exactly. Seven whole months later and the company is still yet to detail what the update will bring for Windows RT devices. So I did some digging.

According to my sources, Microsoft is planning to bring the Start Menu to Windows RT with Update 3, but it won’t be the Start Menu from the Windows 10 RTM. Instead, Microsoft is backporting the DirectUI Start Menu, which for those who don’t know is the Start Menu found in the early Windows 10 Technical Preview builds from October last year.

I’m told the reason they are backporting that version of the Start Menu instead of the newer menu is because the DirectUI Start Menu was built on Windows 8.1 code and is not using any new API’s, whereas the Start Menu found on the Windows 10 RTM is built using XAML and is utilizing a number of new Windows 10 specific API’s.

Windows Insiders who tested the early Windows 10 Technical Preview builds will know that the DirectUI Start Menu is actually pretty awesome, and some even argue that that version of the menu is actually better than the one found on the Windows 10 RTM. It also works pretty well with touch too, which is a plus. Of course, the Start Screen will still be present and can be toggled on or off whenever needed.

Interestingly, I’m told windowed-mode is not in the plans for Windows RT, at least as of writing this. Even with the new Start Menu enabled, Modern UI apps will open in full-screen mode, and desktop apps will exist only on the desktop. I’m also told that Continuum/Tablet Mode and the Universal App Platform are not coming in Update 3 too, again due to those features requiring a number of new Windows 10 API’s and code. Because of there not being any Continuum with Update 3, switching between the Start Menu and Start Screen will be a manual procedure, done via a toggle switch.

Windows RT 8.1 Update 3 is very reminiscent of the infamous Windows Phone 7.8 update released back in 2012, which ported over the new Start Screen from Windows Phone 8 to the dying platform that was WP7. The same is happening here really, Microsoft is porting the Start Menu, a new feature in Windows 10, over to Windows RT which happens to be a dead platform.

The small amount of Windows RT users remaining will likely be left a little disappointed with this update, as many were hoping for more Windows 10 features to find their way over to Windows RT. Unfortunately, it appears the Start Menu is the only noteworthy feature coming, but that’s not so bad. Honestly I’m surprised Microsoft is even working on a new update for Windows RT, as I’m told internally, Microsoft is done with the platform. Microsoft’s new mobile vision lies with Windows 10 on x86/64 tablets and Windows 10 Mobile, not Windows RT.

I was also told that the original launch date for Update 3 was July 29th, alongside Windows 10, but was postponed for reasons which I’m unable to clarify. Update 3 is pretty set in stone at this point, but as always with unreleased software, things can definitely change. What are your thoughts on the upcoming Update 3? Let us know below.